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<div style="position:absolute; top:50px;"><a name="1">Page 1</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:94px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:234px; top:114px; width:135px; height:18px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:18px">经典密码学杂谈 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:147px; width:3px; height:16px;"><span style="font-family: ABCDEE+Calibri,Bold; font-size:16px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:276px; top:167px; width:49px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">卓泽滨 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:187px; width:6px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:209px; width:42px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">摘要： 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:229px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">本文首先介绍加密法的发展历程，后将结合案例介绍两种经典的加密法以及其对应的密
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:249px; width:378px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">码分析方法，最后将总结以上说谈，并简单的介绍其余的经典加密法。 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:269px; width:444px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">关键词：加密法；密码分析；加密法发展史；Vigenere 加密法；keyword 加密法；  
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:290px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:328px; width:40px; height:16px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:16px">概述 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:373px; width:428px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">“芦花滩上有扁舟，</span><span style="font-family: ABCDEE+Calibri; font-size:11px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">俊杰黄昏独自游，</span><span style="font-family: ABCDEE+Calibri; font-size:11px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">义到尽头原是命，</span><span style="font-family: ABCDEE+Calibri; font-size:11px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">反躬逃难必无忧。”</span><span style="font-family: ABCDEE+Calibri; font-size:11px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:393px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这是一首出自《水浒传》中吴用留下的藏头反诗；电视剧《裂变》中汉奸“蝙蝠”也曾
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:413px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">使用数字对应书本页面和文字的方法传递消息给日寇；电影《暗算》中更是提到了黄依
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:433px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">依解决多种密文的具体情节；甚至连动画片《名侦探柯南》也出现了 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">skytale </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密的细
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:453px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">节。事实上，密文不仅存在于荧幕中，而且深入到生活的方方面面，例如用于存储互联
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:473px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">网消息的 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">cookie</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、以及互联网安全中常提到的数字签名、在银行等网站上填写个人信息
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:493px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">时，都会用一定的手段将明文加密成密文传输到在远处的服务器中，可以说，在互联网
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:513px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的世界里，只要有比特流动，就一定会有加密的存在。为此，各大高校还设立了专门的
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:533px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">学科，如密码学、密码分析学、密码史等。不得不说，密码的发展更数学密切相关、大
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:553px; width:459px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">多数的密码学家都兼任数学家的身份，而密码学，这一学科在战争时代更是快速地发展。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:573px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">以下将会介绍密码学的发展史、以及一些经典密码学的典型加密方法和其对应的解密方
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:593px; width:338px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">法的介绍、文章最后会简单地提及现代密码学的一些实现手段。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:634px; width:148px; height:17px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:16px">加密手段与解密手段</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:16px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:681px; width:302px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">常见的加密手段有三种：编码法、加密法和夹带加密法；</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:718px; width:45px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">编码法</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:760px; width:453px; height:34px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">编码法类似于计算机的编译</span><span style="font-family: ABCDEE+Calibri; font-size:7px">1</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">过程，在计算机编译过程中，以 </span><span style="font-family: ABCDEE+Calibri; font-size:11px">ASCII </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">码为例，计算机会将
<br>字母 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">A </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">编译成 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">0x41</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，</span><span style="font-family: ABCDEE+Calibri; font-size:12px">B </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">编译为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">0x42 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">以此类推。我们之所以会很清楚 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">0x43 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应字母 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">C</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:816px; width:288px; height:22px;"><span style="font-family: ABCDEE+Calibri; font-size:10px">                                                             
<br></span><span style="font-family: ABCDEE+Calibri; font-size:5px">1</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">将源代码转化为目标文件的过程（二进制），此处用 </span><span style="font-family: ABCDEE+Calibri; font-size:9px">16 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">进制表示 </span><span style="font-family: ABCDEE+Calibri; font-size:9px">2 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">进制</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:88px; top:840px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:295px; top:840px; width:6px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px">1 
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<div style="position:absolute; top:941px;"><a name="2">Page 2</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1001px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">是因为我们知道 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">ASCII </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">码表，假设我们对 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">ASCII </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">码表一无所知，那么 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">0x44 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">究竟代表什么
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1021px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">我们就不得而知了。而编码法就是这样一种加密手段，即将明文按照一本写好的编码簿
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1041px; width:459px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">翻译成密文，在受到密文后，解读者需要一本一模一样的编码簿才能解读出具体的明文。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:986px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1078px; width:45px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">加密法</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1121px; width:398px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法则不同，一种常用的加密法是将字母转化为数字，例如用一下方法：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1151px; width:333px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">从右图中我们看出 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">a </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应的是 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">11</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，并且令底频率字母 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">j </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">等于 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">i</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1171px; width:333px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这样，每一个字母都有与之对应的数字，而我们可以对数字按照
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1191px; width:333px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">一定的算法进行运算即可得出相应的密文数字，此时，解读者要
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1210px; width:332px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">解读出这些密文，则需要知道形成这一密文的运算法则</span><span style="font-family: ABCDEE+Calibri; font-size:7px">2</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，并更
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1231px; width:230px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">具这一运算法则进行逆运算即可得出明文。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1268px; width:77px; height:16px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">夹带加密法</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:9px">3</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:463px; top:1271px; width:20px; height:11px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:10px">图 </span><span style="font-family: ABCDEE+Calibri; font-size:10px">1 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1310px; width:456px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">夹带加密法是指在不将明文处理成难以解读的密文的情况下，想办法将明文隐藏起来。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1330px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">例如小时候使用隐形笔写字就属于这种加密方法。又如吴用的藏头诗也属于这一类加密
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1350px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">手段。历史资料记载，希腊人在传递消息的时候，曾经把奴隶剃成光头，并将文字刻在
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1370px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">奴隶的头上，待到奴隶的头发长出来时，将奴隶送给对方，以便让对方获得信息。这也
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1390px; width:110px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">属于夹带法的范畴。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1430px; width:59px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">解密手段</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1471px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">常见的解密手段可分为三类，首先是密文攻击，在只有密文的情况下解读出明文叫密文
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1491px; width:459px; height:32px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">攻击；</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">另外还有明文攻击，即在知道某段明文一定存在的情况下</span><span style="font-family: ABCDEE+Calibri; font-size:7px">4</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，将密文解读成明文的手段；
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1531px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">第三种是选取明文攻击，即事先泄露对方感兴趣的话题，使对方针对这一话题的信息加
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1551px; width:459px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">密成密文，这样在截获密文后，就可以清晰的知道密文中一定包含这一话题有关的内容。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1571px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">例如二战中美国暴露给日本中途岛的信息，从而得出 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">AC </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应中途岛这一结论，就是利
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1591px; width:110px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">用了选取明文攻击。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1632px; width:165px; height:17px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:16px">经典密码学的发展历史</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:16px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1684px; width:146px; height:45px;"><span style="font-family: ABCDEE+Calibri; font-size:10px">                                                             
<br></span><span style="font-family: ABCDEE+Calibri; font-size:6px">2</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">即秘钥</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span><span style="font-family: ABCDEE+Calibri; font-size:6px">3</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">也叫夹带法</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span><span style="font-family: ABCDEE+Calibri; font-size:5px">4</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">不一定知道所对应的密文</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:88px; top:1732px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:295px; top:1732px; width:6px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px">2 
<br></span></div><span style="position:absolute; border: black 1px solid; left:70px; top:1690px; width:144px; height:0px;"></span>
<div style="position:absolute; border: figure 1px solid; writing-mode:False; left:413px; top:1152px; width:122px; height:104px;"></div><span style="position:absolute; border: black 1px solid; left:418px; top:1262px; width:107px; height:26px;"></span>
<span style="position:absolute; border: black 1px solid; left:418px; top:1262px; width:107px; height:26px;"></span>
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<div style="position:absolute; top:1833px;"><a name="3">Page 3</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:1878px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:1893px; width:272px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法的出现可以追溯到 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">200BC </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">甚至更远，那个时
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1913px; width:293px; height:51px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">候，希腊作家 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">polybius </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">发明了一种名为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">polybius cipher </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的
<br>加密法，这是一种单码加密</span><span style="font-family: ABCDEE+Calibri; font-size:7px">5</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，其加密手段大致如图 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">1 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">所
<br>示，即将字母对应成数字，当然，可以乱序地将字母填
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1973px; width:293px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">充在该矩阵中得到不同的对应模式。早期的密码还有斯
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:1993px; width:294px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">巴达克人所发明的一种 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">skytale </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的加密工具如右图所示：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2023px; width:432px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">其加密原来是将纸条绕在一根加密棒上，同时在绕在上面的纸条上写下明文，展开
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2043px; width:302px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">后就可以得到乱序的密文了，本质上是一种夹带加密法。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2073px; width:432px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">希伯来人也发明了早期的加密法：如 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">atbah</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">atbash</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">albam </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">等。这些加密法原理上
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2093px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">是将字母与某个密文符号一一对应起来的加密手段。后来罗马大帝凯撒在军事上曾用凯
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2113px; width:335px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">撒加密法对明文进行加密，防止密码泄露。凯撒加密法是将明文
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2133px; width:335px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的字母按标准字母表向后移动若干位，得到一种对应模式；例如
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2153px; width:335px; height:13px;"><span style="font-family: ABCDEE+Calibri; font-size:12px">a </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">d</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">b </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">就对应 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">e</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、明文 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuozebinK </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">ckxrchelq</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">；可以说这
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2173px; width:335px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">些加密法都很容易破解，例如对凯撒加密法 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">K</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，我们可以穷举所
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2193px; width:335px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">有的可能，可以得出密文 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">ckxrchelq </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应的所有字符串，则其中一
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2213px; width:335px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">定存在明文：可以看出，移动三位可以得到真正的明文。于是密
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2233px; width:62px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">码被破解。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2262px; width:432px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">此后的几百年里，出现了一种名单码加密法</span><span style="font-family: ABCDEE+Calibri; font-size:7px">6</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，其中的代表有关键词加密法，直到
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2283px; width:453px; height:13px;"><span style="font-family: ABCDEE+Calibri; font-size:12px">14 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">世纪、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">15 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">世纪仍在欧洲广泛使用。这时候已经出现了对此种加密手段的解密方法。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2303px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">为了弥补这种不足，出现许多新的加密法。如仿射加密法、多文字加密法，这类加密法
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2323px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的解决原理与关键词加密法一样，并且安全性甚至较之更低。单码加密法持续的时间最
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2343px; width:218px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">久，甚至在美国南北战争期间也在使用。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2372px; width:453px; height:34px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">直到 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">16 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">世纪中期，出现了多码加密</span><span style="font-family: ABCDEE+Calibri; font-size:7px">7</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的加密方法。代表有 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">Vigenere </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法，此类加
<br>密法如昙花一现，虽然安全性高，但在数学爆炸性发展的时代，</span><span style="font-family: ABCDEE+Calibri; font-size:12px">Vigenere </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法没过多
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2413px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">久就被解决了。派生的多码加密法还有自动秘钥加密法、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">Nihilst </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法、圆柱面加密法
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2433px; width:398px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">和回转轮加密法，其中在二战期间，联军使用的加密法就是回转轮加密法。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2463px; width:432px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">经典加密法的收官之作是多图加密法，这种加密方法将多个明文字母对应成多个密
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2483px; width:266px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">文，更具安全性。此后则进入现代加密法的时代。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2514px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2576px; width:146px; height:45px;"><span style="font-family: ABCDEE+Calibri; font-size:10px">                                                             
<br></span><span style="font-family: ABCDEE+Calibri; font-size:6px">5</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">即一个明文字母对应一个密文字母</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span><span style="font-family: ABCDEE+Calibri; font-size:6px">6</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">同 </span><span style="font-family: ABCDEE+Calibri; font-size:9px">5 
<br></span><span style="font-family: ABCDEE+Calibri; font-size:5px">7</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">即一个明文字母对应多个密文字母</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:88px; top:2624px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:295px; top:2624px; width:6px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px">3 
<br></span></div><span style="position:absolute; border: black 1px solid; left:70px; top:2581px; width:144px; height:0px;"></span>
<div style="position:absolute; border: figure 1px solid; writing-mode:False; left:373px; top:1878px; width:141px; height:120px;"></div><div style="position:absolute; border: figure 1px solid; writing-mode:False; left:415px; top:2122px; width:104px; height:128px;"></div><span style="position:absolute; border: gray 1px solid; left:0px; top:2725px; width:595px; height:841px;"></span>
<div style="position:absolute; top:2725px;"><a name="4">Page 4</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:2770px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2791px; width:148px; height:17px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:16px">代表性的加密法介绍</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:16px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2842px; width:87px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">关键词加密法</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2885px; width:432px; height:13px;"><span style="font-family: ABCDEE+Calibri; font-size:12px">keyword </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法，要求首先选取一个关键词，去掉关键词内的重复字母，如选取
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2905px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">“</span><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuozebin</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">”后的变为“</span><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuoebin</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">”，然后将 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuoebin </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">放在开头（或任意位置开始），其
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:2925px; width:362px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">余的位置按照标准字母表的顺序填入，并与标准字母表对应，如下：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2957px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:2985px; width:233px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这样用此对应关系，明文转化为密文。例如</span><span style="font-family: ABCDEE+Calibri; font-size:12px">: 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:3015px; width:38px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">明文：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:3049px; width:429px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">sunnysaidthatshelovemebutidontknowthatwhetheritistruthorjustatric
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3067px; width:17px; height:10px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">k</span><span style="font-family: ABCDEE+Courier New; font-size:5px">8</span><span style="font-family: ABCDEE+Courier New; font-size:8px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:3095px; width:50px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密后：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:3129px; width:429px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">qsjjxqzaornzrqnefktegehsraokjrdjkvrnzrvnerneparaqrpsrnkpcsqrzrpau
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3149px; width:13px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">d 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3183px; width:31px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">解析</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3224px; width:456px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">因为关键词是任意的，不可能穷举，我们可以采用频率分析的方法，解决此类的问题。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3244px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">因为一一对应的单码加密法保留了用此频率不变的特征，根据这一特征，我们可以统计
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3264px; width:338px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">出字母之间的对应关系。以下统计了各个词的频率，从柱形图中</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3284px; width:338px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">我们可以清晰地看出明显的波峰波谷，根据英语的用词频率，可</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3304px; width:122px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">以估计出以下对应关系</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3325px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3345px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3365px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3385px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3492px; width:216px; height:22px;"><span style="font-family: ABCDEE+Calibri; font-size:10px">                                                             
<br></span><span style="font-family: ABCDEE+Calibri; font-size:5px">8</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">为了方便加密和解密，一般明文中不包括符号和空格</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:88px; top:3516px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:295px; top:3516px; width:6px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px">4 
<br></span></div><span style="position:absolute; border: black 1px solid; left:70px; top:3497px; width:144px; height:0px;"></span>
<div style="position:absolute; border: figure 1px solid; writing-mode:False; left:86px; top:2948px; width:422px; height:56px;"></div><div style="position:absolute; border: figure 1px solid; writing-mode:False; left:407px; top:3266px; width:125px; height:234px;"></div><div style="position:absolute; border: figure 1px solid; writing-mode:False; left:135px; top:3336px; width:203px; height:43px;"></div><span style="position:absolute; border: gray 1px solid; left:0px; top:3617px; width:595px; height:841px;"></span>
<div style="position:absolute; top:3617px;"><a name="5">Page 5</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:3662px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:406px; top:3796px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3816px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3836px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3856px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3876px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3896px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3916px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3936px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3956px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3975px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">当然，由于截获的密文数量不足，统计未免有不当之处。也可以采用双联字母的方法估
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:3995px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">计，如字母组合：</span><span style="font-family: ABCDEE+Calibri; font-size:12px">th</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">he</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">er </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">频率高，可以猜测高频率的组合可能是此三者之一，此外
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4015px; width:218px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">还有三联字母组合的方法确定对应模式。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4036px; width:2px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4074px; width:101px; height:15px;"><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px">Vigenere </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">加密法</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4117px; width:432px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这是一种多码加密法，一个明文字母对应多个密文字母，同样选取关键词，如
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4137px; width:449px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">“</span><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuoebin</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">”，重复关键词并与标准顺序的字母表对应，即可形成一种加密方式。即：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4169px; width:148px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px">zhuoebinzhuoebinzhuoebinzh 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4198px; width:2px; height:10px;"><span style="font-family: ABCDEE+Calibri; font-size:10px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4197px; width:147px; height:12px;"><span style="font-family: ABCDEE+Calibri; font-size:12px">abcdefghyzklmnopqlstuvwxyz 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4216px; width:386px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这样明文与秘钥通过查找 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">Vigenere </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">表可以得出密文，如 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">za </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">z</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，</span><span style="font-family: ABCDEE+Calibri; font-size:12px">hb </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">对应 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">i 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4236px; width:74px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这样明文为：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4267px; width:429px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">sunnysaidthatshelovemebutidontknowthatwhetheritistruthorjustatric
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4287px; width:13px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">k 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4308px; width:50px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">密文为：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4339px; width:429px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">rbhbxwbqqsouhrlftbulgsayuqqnunymsxbuzaqvdximehacgsvvbunydirxbbehj
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4359px; width:13px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">e 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:88px; top:4408px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:295px; top:4408px; width:6px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px">5 
<br></span></div><div style="position:absolute; border: figure 1px solid; writing-mode:False; left:70px; top:3677px; width:335px; height:128px;"></div><span style="position:absolute; border: gray 1px solid; left:0px; top:4509px; width:595px; height:841px;"></span>
<div style="position:absolute; top:4509px;"><a name="6">Page 6</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:297px; top:4554px; width:2px; height:9px;"><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4573px; width:31px; height:15px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:13px">解析</span><span style="font-family: ABCDEE+Calibri,Bold; font-size:13px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4620px; width:145px; height:15px;"><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:14px">IC </span><span style="font-family: b'ABCDEE+\xba\xda\xcc\xe5'; font-size:13px">法估算关键词的长度</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:14px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4663px; width:2px; height:10px;"><span style="font-family: ABCDEE+Calibri; font-size:10px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4693px; width:78px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">定义 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">IC </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">值为：</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4722px; width:303px; height:14px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">其中 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">f</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">α是密文中α字母出现的频率，而 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">N </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">密文的长度</span><span style="font-family: ABCDEE+Calibri; font-size:7px">9</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4753px; width:432px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">计算出 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">IC </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">之后，例如上例所得出的 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">IC </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">值为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">0.04382</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">，查表可值，</span><span style="font-family: ABCDEE+Calibri; font-size:12px">keyword </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">的长度可
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4773px; width:84px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">能是：</span><span style="font-family: ABCDEE+Calibri; font-size:12px">5,6,7,8</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">；</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4809px; width:199px; height:15px;"><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:14px">Kasiski </span><span style="font-family: b'ABCDEE+\xba\xda\xcc\xe5'; font-size:13px">法确定具体的关键词长度</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:14px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4853px; width:186px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">从密文中看出，</span><span style="font-family: ABCDEE+Calibri; font-size:12px">bu </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">一共出现了两次</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4887px; width:429px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">rbhbxwbqqsouhrlftbulgsayuqqnunymsxbuzaqvdximehacgsvvbunydirxbbehj
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4907px; width:13px; height:8px;"><span style="font-family: ABCDEE+Courier New; font-size:8px">e 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4933px; width:432px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">根据数学推导，可以知道，重复字符串之间间隔的字符串长度为关键词长度的整数
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:4953px; width:253px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">倍，据此我们可以推断出关键词长度为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">16/2=8</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:91px; top:4983px; width:432px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">得知关键词长度后，将密文分为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">8 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">组，第一组为第 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">1</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">  9</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">、</span><span style="font-family: ABCDEE+Calibri; font-size:12px">  17…</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">组成，以此类推，
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5003px; width:278px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">这样就可以按频率法分别求出各自的对应关系即可。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5042px; width:52px; height:17px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:16px">结尾：</span><span style="font-family: b'ABCDEE+\xb5\xc8\xcf\xdf Light'; font-size:16px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5089px; width:459px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">关于经典的密码技术还有很多；最典型的该属回转轮加密法了，也称为 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">Enigma </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">加密法。
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5109px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">屏幕上的惊悚跌宕的剧情在现实中也是同样存在的。比如《比尔密码》就是属于这类的
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5129px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">传奇。传说比尔（</span><span style="font-family: ABCDEE+Calibri; font-size:12px">Beale</span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">）于 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">1817 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">年得到了一笔巨大的财富，并将一个盒子交给他的朋
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5149px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">友，告诉他 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">10 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">年后没回来就打开盒子。结果 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">10 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">年后朋友打开时发现里面竟然是写满数
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5169px; width:266px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">据的纸。由此比尔密码花费了许多人毕生的生命。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5189px; width:453px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">自 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">2013 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">年 </span><span style="font-family: ABCDEE+Calibri; font-size:12px">6 </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">月棱镜计划破产后，网络安全成为众人关注的问题。如何才能防止自己的
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5209px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">个人信息被监听？如何才能避免黑客窃取自己的账号密码？如何防止医院的医疗记录
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5229px; width:350px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">被盗？如何在战争中获取敌人的情报？都应该是值得思考的问题。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5249px; width:453px; height:12px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">经典加密法远不止如此，而基于电子技术的现代加密法更是引人入胜。道高一尺魔高一
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<br></span><span style="font-family: ABCDEE+Calibri; font-size:5px">9</span><span style="font-family: ABCDEE+Calibri; font-size:9px">  </span><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:9px">不计入空格和标点符号</span><span style="font-family: ABCDEE+Calibri; font-size:9px"> 
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<div style="position:absolute; top:5401px;"><a name="7">Page 7</a></div>
<div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5461px; width:410px; height:13px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:12px">丈，有密码就会有密码分析，人类的技术就在于挑战中进化，在数学中升华。</span><span style="font-family: ABCDEE+Calibri; font-size:12px"> 
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<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5522px; width:351px; height:10px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:10px">[1]〔美〕Richard Spillman. 经典密码学与现代密码学. 清华大学出版社. 
<br></span></div><div style="position:absolute; border: textbox 1px solid; writing-mode:lr-tb; left:70px; top:5542px; width:393px; height:10px;"><span style="font-family: b'ABCDEE+\xcb\xce\xcc\xe5'; font-size:10px">[2] Lori Andrews.I Know Who You Are and I Saw What You Did.中国友谊出版社. 
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<br></span></div><div style="position:absolute; top:0px;">Page: <a href="#1">1</a>, <a href="#2">2</a>, <a href="#3">3</a>, <a href="#4">4</a>, <a href="#5">5</a>, <a href="#6">6</a>, <a href="#7">7</a></div>
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